1. Field of the Invention
The present invention relates to a polygonal radiation module having radiating members without a light guiding board, especially to a radiating surface applied to a backlight module or other like emitting structure that does not require the light guiding board to achieve an even emission from a diffusion plate.
2. Description of the Related Art
Generally, in order to guide light for achieving an appropriate and multi-angled reflection, the backlight module would be commonly installed with a light guiding board. “A side-edged backlight module” disclosed in R.O.C. patent No. M359718 includes a plurality of LEDs, a light guiding board, a bright enhancement film, and a diffusion plate. Wherein, each LED has a radiating surface, and the radiating surfaces of the LEDs face to the same direction. The light guiding board disposed at one side of the LEDs has an incident plane, an emission plane, and a bottom. Wherein, the incident plane of the light guiding board faces to the radiating surfaces of the LEDs, the emission plane of the light guiding board adjacently connects to one side of the incident plane, and the bottom of the light guiding board disposed in correspondence with the emission plane adjacently connects to the other side of the incident plane, so that a plurality of micro-optical structures and flat areas are formed. Herein, the flat areas and the incident plane converge on a boundary. Moreover, the flat areas are respectively disposed in the relationship to the radiating surface, the bright enhancement film is provided above the emission plane of the light guiding board, and the diffusion plate is set upon the bright enhancement film. However, some shortcomings exist in such disclosure:    1. LCDs that mostly employ the backlight module are developed thinner. However, the conventional light guiding board of the backlight module is unfavorable for decreasing the thickness of the integral LCD. Further, since the light guiding board absorbs the light source, the output efficiency of the backlight module would thence be lowered. Additionally, the installation of the light guiding board adversely increases the manufacturing procedure, which consequently raises the cost of producing the backlight module.    2. The light sources of the backlight module are respectively disposed at the two sides of the light guiding board. As a result, the illumination would perform well at the two sides of the light guiding board; however, the center of the light guiding board would possess a weak illumination.
“Planar light source device and display device using the same device” disclosed in U.S. Pat. No. 7,350,951 replaces the typical light guiding board by varying an optical reflector disposed at a bottom thereof to construct an emission structure. Whereby, the output of the light could be increased. However, shortcomings still exist in such disclosure:
Although such disclosure conquers the poor output efficiency from the light guiding board, the side-edged light source still merely provides the two sides of the light guiding board with higher illumination, but the center thereof with lower illumination. Moreover, since the optical reflector has its middle section raised, certain light sources may not widely reflect within the optical reflector. As a result, the backlight module still provides uneven illumination.